A wire is a length of metal that has been drawn out into a thread. Wire is usually flexible, circular in cross section, and uniform in diameter. Wire diameters general range from about 0.001 to 0.5 inch (0.025–12.7 millimeters). To manufacture wire, normally a hot-rolled metal rod pointed at one end is coated with a lubricant, threaded through a tungsten-carbide or diamond die and attached to a drum called a draw block. The draw block is rotated and wire of a diameter, or gauge, determined by the diameter of the die is drawn until the entire metal rod is reduced to wire.

Steel, iron, aluminum, copper, and bronze are the metals most widely used for wire making, although others, including gold, platinum and silver, are used as well. Copper and aluminum are preferred for electrical wiring, since they combine high ductility with low resistance to electric current.